. PREHEAT OVEN TO 180 DEGREES CELCIUS. LIGHTLY GREASE A 20CM ROUND OR SQUARE CAKE TIN.. SIFT COCOA POWDER, FLOUR AND BAKING POWDER INTO A LARGE BOWL. STIR IN SUGAR AND SET ASIDE.. PUREE BEETROOT IN A FOOD PROCESSOR, THEN ADD EGGS ONE AT A TIME, MIXING AFTER EACH ADDITION. ADD VANILLA AND OIL AND WHIZ UNTIL SMOOTH.. MAKE A WELL IN THE CENTRE OF DRY INGREDIENTS, ADD BEETROOT MIXTURE AND LIGHTLY MIX.. POUR INTO CAKE TIN AND BAKE FOR 50 – 60 MINUTES, OR UNTIL A SKEWER INSERTED INTO THE CENTRE COMES OUT CLEAN. THE CAKE MIGHT NOT RISE A GREAT DEAL, AND THE TOP WILL CRACK.. REMOVE FROM OVEN AND COOL FOR 15 MINUTES IN PAN, THEN REMOVE TO A WIRE RACK TO COOL COMPLETELY.. DUST WITH ICING SUGAR TO SERVE.